WO03/056141A1 describes a gear. The gear, divided into two axially adjacent spur gears, has a torsion spring in the form of a circular ring segment, wherein a slot is formed between the two peripherally mutually opposing spring ends, in which slot two cams engage which are each assigned to one of the two spur gears, wherein one of the cams is assigned to one of the two spring ends and the other cam is assigned to the other spring end. When the gear is mounted in the gear mechanism, the two spur gears mesh play-free with the engaged gear. In the installed rotational position of the two spur gears, the cams arranged peripherally behind each other are offset to each other in the peripheral direction, such that the cams push the spring ends of the torsion spring apart, enlarging the slot. The pretension and stiffness of the torsion spring are essential for smooth operation of such a gear mechanism. If a large pretension and large stiffness are required, a correspondingly large torsion spring must be provided and pretensioned. In many applications, the installation space available for the torsion spring is very limited, so enlargement is only possible within limits.